This invention relates to compositions comprising polyamides, polyolefins and ethylene vinyl alcohol copolymers useful as compatibilizers, and related processes and articles made therefrom.
Blends of polyamides and polyolefins are well known. Such blends have been described in the art as being homogeneous and heterogeneous. A review of the distinction between homogeneous blends and heterogeneous blends is found in U.S. Pat. No. 4,410,482 and related U.S. Pat. No. 4,444,817. These references disclose a variety of dispersant materials used to form homogeneous blends of polyolefins and polyamides. U.S. Pat. No. 4,410,482 is directed to "heterogeneous" blends of polyolefins and polyamides. Such a heterogeneous composition is useful in forming articles having improved barrier to fluid permeation and improved mechanical properties. These patents disclose that a polyolefin and a condensation polymer incompatible with the polyolefin can be formed into an improved composition by using an alkylcarboxyl-substituted polyolefin as a compatibilizing agent. A review of the compatibilizers used in these referenced patents is found beginning at column 6, line 4, of U.S. Pat. No. 4,410,482.
U.S. Pat. Nos. 3,857,754 and 3,975,463 disclose blends of compositions of polyolefin, saponified ethylene-vinyl acetate copolymer (also known as ethylene vinyl alcohol copolymer) and a carbonyl containing thermoplastic polymer.
U.S. Pat. Nos. 4,468,427 and 4,427,825 disclose a composition comprising a polyamide, preferably polyepsiloncaprolactam and from 1 to 65 percent of an ethylene vinyl alcohol copolymer composition. The composition is indicated to be a heterogeneous melt-blended composition wherein there are regions of ethylene vinyl alcohol copolymer having an average diameter of less than 500 angstroms in the polyamide.